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where to get shear pins?


Finn
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The pin on my Gaz winch is 5mm. That is a pretty helty winch, 5 tons I seem to recall? I had no pin so I have used a 6mm 12.9 cap screw and turned the shank down (I needed an M6 thread under the head)

I was trying to pull a Zil out with it a few weeks back so the 5mm pin is definitely up to the job. It is however on the PTO shaft side connecting to the worm so much lighter loaded

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Does anyone know what kind of bold I could use instead of a shear pin?

Cheers,

Finn

I use a few on agricultural stuff and they are usually 8.8. We now use normal bolts as they are much cheaper and appear no different (I know there used to be a difference at college!)

If you think they break too easy, up the strength or drill out to the next size up.

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Aren't the std ones made of brass? if so this has a much lower shear strength than mild steel/8.8 bolt.

I'd start with a machined groove , say down to 4mm and do a bit of winching with a known load - a swb with the wheels locked up on dry tarmac. If it will drag it without shearing it should be about right.

.....having said that I know several people that run with HT bolts or even bolt the shear drive flanges together..

cheers

Steveb

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Well, I found some at blanchards.

I have a side question.

How does this work on a defender PTO, does these also have shear pins? Have never seen one..

Cheers,

Finn

in the book I referred to above, it says 'Overlaod Protection Device' can be preset, what the OPD is I don't know, possibly a clutch with a adjustable slip.

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The LT230 drop box pto has an adjustable sprung ball clutch - the two drive flanges have holes drilled that the ball seats into with most of the ball protruding, the driven plate then has large belleville washers between it and a large ring nut - tighten the nut = more pressure on the balls in the seats . At overload the plate moves against the spring force and the balls roll in a machined track in both drive flanges.

The ring nut is locked by a grub screw iirc

...these can also be tightened to the point they are fully locked..

cheers

Steveb

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Ok,

I added some drawings out of a parts book I found on my harddrive.

Lets say you have pulled something way too heavy. Do you need to replace anything, or is it just a case of putting everything (the balls) back at its place and tighten the nut?

Cheers,

Finn

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